The overall goals of this project are to identify the genes responsible for all the peroxisome biogenesis disorders (PBD) complememtation groups and to understand their role in peroxisome assembly. We plan to continue our studies of the role of PMP70 and related ABC transporters in the peroxisomal membrane as well as identify and characterize new genes necessary for peroxisome biogenesis. In this regard, currently, we are aware of at least 11 PBD complementation groups, two of which (CG 2 and 10) are already explained at the molecular level. To identify the remaining 9 or more genes responsible for the PBD we will use a variety of strategies to isolate candidate PBD genes taking advantage of the large collection of well characterized PBD patient materials assembled during the previous years of this Program Project as well as resources developed to test candidate cDNAs and conform their role in a specific PBD complementation group.